Internal combustion engines conventionally include a crank which is part of the engines power output shaft. The reciprocating power piston is connected to the crank by a connecting rod so that the piston's linear reciprocating motion is converted to rotational motion of the power shaft. The coupling between the connecting rod and the crank is such that the moment arm is less than the maximum when maximum force is applied by the piston.
The force is applied to the piston by the expansion of the combusting air/fuel mixture. As the expansion increases the moment arm increases and, simultaneously, the force from the expansion decreases. It is well known in the art that this conventional relationship of piston, connecting rod and crank effects less than the maximum available torque to the power shaft. This conventional arrangement wastes power as heat. Many earlier attempts have been made to increase mechanical efficiency of the piston engine by eliminating the angular and moment arm changes that the connecting rod undergoes in its relationship with the power output shaft and power piston. These attempts have serious drawbacks. Some do not increase the mechanical efficiency, i.e. U.S. Pat. No. 1,667,213 issued to Marchetti on Apr. 24, 1928. Others may increase the efficiency but sacrifice sturdiness or reliability as, for example, U.S. Pat. No. 4,363,299 issued Dec. 14, 1982 to Bristol and U.S. Pat. No. 4,498,430 issued Feb. 12, 1985 to Giuliani.